1. Field of the Invention
This invention relates to an outboard motor, and more particularly, to an outboard motor in which a shift unit for switching a shift position is provided in the middle of a drive shaft that transmits rotational power from an engine to a propeller shaft.
2. Description of the Related Art
In some outboard motors, a shift unit has a clutch body moved to switching a shift position and an actuator for driving the clutch body. The clutch body is provided in a lower portion of the outboard motor, such as in the middle of the drive shaft that transmits rotational power to a propeller shaft corresponding to a driving power source or between the drive shaft and the propeller shaft. Meanwhile, the actuator is provided in an upper side of the outboard motor, such as in the vicinity of the engine. In this manner, in some outboard motors of the prior art, the clutch body of the shift unit and the actuator for driving the clutch body are positioned far from each other. In addition, the actuator shifts the clutch body using a link mechanism. For example, in Patent Document 1, the actuator arranged vertically in the middle of the outboard motor shifts the clutch body arranged in a lower portion of the outboard motor using a shift rod.
However, in this configuration, rattling (slack), deflection, or torsion of the link mechanism provided between the actuator and the clutch body reduces an actual shift amount of the clutch body relatively to a driving force generated from the actuator. For this reason, it is difficult to shift the clutch body with high accuracy. In addition, rattling, deflection, or torsion of the link mechanism degrades responsiveness. Furthermore, a loss is generated in the transmitted driving force due to friction of the link mechanism between the actuator and the clutch body and the like. For this reason, in order to reliably shift the clutch body, it is necessary to increase the driving force of the actuator. However, if the link mechanism suffers from deflection, torsion, and the like, it is difficult to transmit a strong force.